Tyler Watt has posted over on his blog a new post showing some tips on the use of SDR#. He makes use of animated gifs to clearly show the action in SDR# that he is performing. If you’ve been wanting to learn more about how to use SDR#, or what the various options do, check out his guide.
Last month two new SDR# plugins where released on rtl-sdr.ru. The first is TimeShift SDR. This plugin creates a buffer which allows you to listen to any signal at any point in time on the waterfall within the buffer time. It is very useful for catching signals that you might have otherwise missed by being too slow to click on them. Update: Turns out Timeshift SDR isn’t exactly new. But it has recently been updated to work on the latest SDR# releases.
The second plugin is a Digital Audio Processor which adds in a squelch slider bar, an audio inverter, an audio band-pass filter and a de-emphasis filter.
The latest version of SDR# has now been updated to include a noise blanker plugin. A noise blanker can reduce impulsive noises like those created by spark gaps and electric motors. Other SDR programs like Linrad and HDSDR have had noise blanker functions for a while so this is a welcome addition to SDR#. Below is a comparison of the noise blanker turned on and off on a noisy CW signal.
To update SDR# to the latest version simply run install.bat again. Take note that updating will remove any plugins you have added to the SDRSharp.exe.Config file so you may wish to save it first.
Noise Blanker Off
[audio https://www.rtl-sdr.com/wp-content/uploads/2014/03/nb_off.mp3]Noise Blanker On
[audio https://www.rtl-sdr.com/wp-content/uploads/2014/03/nb_on.mp3]SDR# has recently been updated to include an IF stage digital noise reduction algorithm. Previously digital noise reduction could be done at the audio output stage, but now it can be done to the IF signal as well. Performing digital noise reduction on the IF stage appears to work much better than at the audio stage. Update SDR# by running the install.bat file again.
Here are some comparison audio files tested on a noisy NFM voice signal for listening.
Original Signal
[audio https://www.rtl-sdr.com/wp-content/uploads/2014/03/IF_NR_OFF.mp3]IF Noise Reduction (set to -12 dB)
[audio https://www.rtl-sdr.com/wp-content/uploads/2014/03/IF_NR.mp3]Audio Noise Reduction (set to -80 dB)
[audio https://www.rtl-sdr.com/wp-content/uploads/2014/03/AF_NR.mp3]
SDR# is the most commonly used Software Defined Radio receiver GUI that is used with the RTL-SDR. Natively, it runs on Windows, but since it is written in C#, it can also run on Mac OSX and Linux with Mono. Installing SDR# on OSX using Mono is a little more complicated compared to simply running it on Windows however.
To help with this, Jan Szumiec has written a simple guide on installing SDR# using Mono on OSX. The guide includes the steps of installing Mono, the Xamarin Studio Mono IDE, the rtl-sdr libraries and then compiling the SDR Sharp sources and symlinking the Mono runtime to the native libraries.
Update: This is no longer possible as the SDR# code is not available anymore.
Recently an RTL-SDR.com reader wrote in to let us know about a fork of SDR# written by “Gubo682” which has some added features. Note you will need to be a member of the SDR# Yahoo group to access the download page linked above. The added features and changes to SDR# are
Frequency Manager
– Names show up in spectrum
– Scan button for simple scanning through current group
– Selected group remembered after restart
– Adding new entry: group defaults to current group
– Simple DMR support (see Tips)
– SHIFT click (or SHIFT ENTER) will select according relais input frequency for 2m/70cmSpectrum Display
– When dragging spectrum left/right, holding SHIFT will keep frequency constantWaterfall Display
– With the new HF [Radio Freqeuency]/AF [Audio Frequency] button waterfall can be switched to AF. Cursor will be annotated with AF frequency.
– Splitter position (hopefully) restored properly after restartRecording
– AF recording pauses if squelch closedDX Cluster Plugin
– Displays DX cluster stations in the spectrum
– Displays currently on-air SW radio stations in spectrum (data from http://www.eibispace.de/)
In addition there is also now a notch filter with adjustable bandwidth which can be applied by right clicking in the new AF (Audio Frequency) mode of the waterfall.
To use with the RTL-SDR, you will need to download the SDRSharp_gubo68_4d.zip file, run install.bat and then manually un-comment the line
You can follow the development of this modified SDR# on the SDRSharp Yahoo group, and specifically in this Yahoo Groups thread.
CTCSS is an acronym for Continuous Tone-Coded Squelch System and is a system that is used in shared two way radio systems. It is common for a single radio channel to be shared over a number of user groups for frequency use efficiency. CTCSS uses a special tone to identify each group of users, and this tone is used to prevent a group hearing radio chatter from another group sharing the channel.
Over on the SDR# Yahoo Groups forum, a CTCSS detector plugin for SDR# has been posted. The plugin can detect CTCSS tones and provide a squelch for the desired tone. The latest version of the plugin can be downloaded from this link.
LevelMeter is a new plugin for SDR# which displays an RX power meter of the currently tuned frequency. It can show either the RX power of the current VFO frequency, the average RX power in Bandwidth, or the peak RX power in Bandwidth.
